package 考试;

import java.util.Scanner;

public class 题1 {
//    给定一个字符串，剔除重复的字符，并返回不重复字符，例如：给定字符串 abgadb ，则整
//    理后得到 abgd 。
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String s = sc.nextLine();
        String s1 = function1(s);
        System.out.println(s1);
    }
    public static String function1(String s){
        StringBuffer sbre = new StringBuffer("");
        for (int i = 0; i < s.length(); i ++) {
            char ch = s.charAt(i);
            int first = s.indexOf(ch);
            int end = s.lastIndexOf(ch);
            if (first  == end || first == i) {
                sbre.append(ch);
            }
        }
        return sbre.toString();
    }

}
